Examine source code of BrowserSelector

{
  "manifest_version": 2,
  "name": "__MSG_extName__",
  "version": "1.0.0",
  "description": "__MSG_extDescription__",
  "permissions": [
    "nativeMessaging",
    "tabs",
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "128": "misc/128x128.png"
  },
  "applications": {
    "gecko": {
      "id": "browserselector@clear-code.com",
      "strict_min_version": "78.0"
    }
  },
  "default_locale": "ja"
}